Windows 10 was installed on over 75 million PCs in a month

Windows 10, the latest operating system from Microsoft, has been
installed on over 75 million PCs, according to the company's
Windows marketing chief Yusuf
Mehdi on Twitter.

After one week of availability, Microsoft announced that Windows
10 had been installed on
14 million machines and that number has since more than
quadrupled in a month.

The Windows 10 rollout has come in waves, the first of which was
a free upgrade to existing Windows 7 and 8 users. As the new
operating system is free, the comparison to Windows 8 is
imperfect, but the company sold
almost 40 million licenses in the first month of Windows 8's
release.